[cDNA of cattle alpha S1-casein: cloning and nucleotide sequence]

Abstract

The nucleotide sequence of recombinant plasmids representing a full-size cDNA of cow alpha s1-casein was investigated. The corresponding mRNA consists of 1133 nucleotides except for poly(A) and includes 642 nucleotides of the coding region, 63 nucleotides of 5'- and 428 nucleotides of the 3'-noncoding regions. A comparative analysis of nucleotide sequences of cow alpha s1-casein and guinea pig B-casein showed that the homology in the 5'-nontranslatable region is 90.5%, that of a precasein single peptide is 82.22%, while that of the major polypeptide in the coding region is 64% without taking into account the blank spaces. The homology is higher in the 3'-noncoding region than in the coding region and makes up to 72%. The data obtained testify to the high degree of conservatism of sequences in casein mRNA noncoding regions as well as to functional and regulatory role of these sequences in gene expression of caseins.